This research is to develop an x-ray tube for the new generation of multi- detector array CT scanners that will have a slice life greater than ten million slices. The "ten million slice life" x-ray tube will be a non-replaceable component; it last the life of the CT scanner, thus resulting in significant cost reductions for hospital use. During Phase I, an x-ray tube meeting the performance requirements of multi-detector array CT scanners will be built and life tested to determine the magnitude of slice life limiting factors. The information learned will be useful for extending the slice life of all CT scanner x-ray tubes. In proposed Phase II, the tube design will be modified based on the life test results. Further extensive life testing will then be conducted under CT scanner operating conditions. The resulting improved x-ray tube design could be installed as a permanent component in the new generation of multi- detector array CT scanners, and conventional helical CT scanners. During Phase III, the "ten million slice life" x-ray tube will be manufactured for use in CT scanners. PROPOSED COMMERCIAL APPLICATIONS: The x-ray tube with a "ten million hour slice" life would be a non- replaceable component in the CT scanner. It would last for the life of the scanner, like a heat exchanger, power supply or computer. This would result in significant cost reductions for CT scanning. The cost of replacement tubes would be eliminated, as well as the costly tube replacement in the hospital.